零零恭、零零喜、零零发（周星驰 饰）、零零财是宫廷四大高手，专职保卫皇帝（张达明 饰）的安全。虽号称四大高手之一，零零发实际上只会搞些小发明完全不会武功，某次因为未完成皇帝交办的捉拿江湖四大怪杰的任务，他被开除出宫。回家后，零零发开了一家妇科诊所，时常会用一些小发明讨得老婆（刘嘉玲 饰）心花怒放，日子也算怡然自乐。 金国以“天外飞仙”尸体为由将皇帝从宫中骗出，并伺机杀死了紧跟皇帝的三大高手，关键时刻，零零发用他发明的“直升机”和“机关枪”救皇帝一命。不死心的敌手随后派来名妓琴操（李若彤 饰）引诱零零发，零零发与老婆将计就计演起双簧。
Based on the novel by Karel Capek, the prominent Czech writer of the early 20th century who coined the word robot for his play R.U.R., the story revolves around a discovery of Krakatit - a powerful explosive - by Prokop, an experimental scientist who, following an accidental explosion in his lab, slips in and out of delirium. When he realises that, in a delirious period, he has given the formula for making Krakatit to one of his colleagues, he tries to find the man, who does not realize how dangerous a thing Krakatit is. In the process, he nearly gives his discovery away again to foreign interests, a group of anarchists, and even greater forces of darkness...
